The present invention relates to a clinically applicable non coating therapeutic preparation for onychomycosis for external use comprising a medium chain fatty acid triglyceride as a nonvolatile component and having excellent nail permeability and excellent medicinal effect and formulation physical properties. In particular, the present invention provides a therapeutic preparation for onychomycosis for external use comprising an antifungal active substance such as efinaconazole, a volatile ingredient, an additive such as medium chain fatty acid triglyceride and a permeation promoter such as ethyl lactate. This preparation has remarkably improved nail permeability and has superior properties as pharmaceuticals from the viewpoint of efficacy and formulation physical properties.本發明係提供含有以中鏈脂肪酸甘油三酯作為不揮發性成分之非被膜系外用灰指甲治療劑，為指甲透過性高，藥效及製劑物性優良，適用於臨床之外用灰指甲治療劑。尤其本發明係提供含有艾氟康唑等抗真菌活性物質、揮發性成分、中鏈脂肪酸甘油三酯等添加劑及乳酸乙酯等透過促進劑之外用灰指甲治療劑。本製劑顯著的提昇指甲透過性，從藥效及製劑物性觀點而言，作為醫藥品，具有優越之特性。
